Heterotrophic potential of Phormidium and other blue-green algae
Several algal types were tested for the ability to assimilate a variety of organic compounds including glucose, sucrose, glycerol, acetate, and a variety of amino acids. Axenic cultures of Phaeodactylum tricornutum, Cricosphaera sp., and Dunaliella tertiolecta failed to take up any of the compounds tested. Axenic cultures of the filamentous blue-green algae Phormidium sp. and Lyngbya sp. took up all of the test substrates, as did the "olive-green cells" (a non-bacteria-free sample of marine algal cells described as olive-green cells by other workers). The results of experiments to determine uptake rates over the range 10−7 to 10−3 molar substrate, rates of uptake at 18, 24, and 32C, and rates of uptake in the presence of the metabolic inhibitors dinitrophenol (DNP) and carbanyl cyanide m-chlorophenylhydrazone (CCCP) indicated that uptake of the organic compounds tested by the filamentous blue-green algae tested is not by an active transport mechanism.